File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

APP file extension

Mac OS X Application

Executable Files

ASF file extension

Advanced Systems Format File

Video Files

CPL file extension

Windows Control Panel Item

System Files

CRDOWNLOAD file extension

Chrome Partially Downloaded File

Misc Files

CSR file extension

Certificate Signing Request File

Web Files

DNG file extension

Digital Negative Image File

Camera Raw Files

MPG file extension

MPEG Video File

Video Files

ODT file extension

OpenDocument Text Document

Text Files

PPT file extension

PowerPoint Presentation

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RSS file extension

Rich Site Summary

Web Files

RTF file extension

Rich Text Format File

Text Files

TAR file extension

Consolidated Unix File Archive

Data Files

TGA file extension

Targa Graphic

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files